Flow switch



FIG. 1 shows a front view of a flow switch showing my new design;

FIG. 2 shows a rear view thereof;

FIG. 3 shows a right side view thereof;

FIG. 4 shows a top view thereof;

FIG. 5 shows a bottom view thereof; and,

FIG. 6 shows a top, front and right side perspective view thereof.

The broken lines showing of unclaimed portions form no part of the claimed design. 

The ornamental design for a flow switch, as shown and described. 